My invention relates to a pulse interpolation method and apparatus therefor. More specifically, the invention pertains to circuit arrangements for restoring received amplitude modulated pulses to an original analog signal form.
It is known to convert an analog signal representing the measured value of a function at a remote location into a pulse signal form, e.g., a series of discrete amplitude modulated pulses, for transmission over a communication channel to a central location. In order to register and/or indicate the condition of the remote function in a form equivalent to the original measurement, it is then necessary to restore or reconstitute the received pulse signals into an analog signal at least substantially equivalent to that analog signal initially existing at the remote location. This reconversion should be as accurate and reliable as possible. However, present circuit arrangements for converting from a series of pulse signals of varying amplitude to an analog signal, because of delay times and other inherent characteristics and operating principles, do not reproduce an analog signal substantially equivalent to the original form as consistently and accurately as desired. An improved arrangement is needed and desirable.
Accordingly, an object of my invention is an improved method for converting pulse signals of varying amplitudes into the analog signal function which the pulses represent.
Another object of the invention is improved apparatus for reconverting variable amplitude pulses into an analog signal substantially equivalent to that signal from which the pulses were derived.
A further object of the invention is a circuit arrangement for use at a central station in a remote function indicating system to reconvert pulse signals of varying amplitude, received from a remote station and representing an analog measurement of the condition of the indicated function, into an analog signal substantially equivalent in derivatives and magnitude to that signal measured at the remote station.
Yet another object of my invention is a method of accurately converting discrete variable amplitude pulse signals into an equivalent analog signal function by successively producing and summing overlapping triangle or cos.sup.2 .omega.t areas, each having a height equal to a selected pulse signal and a base equal to twice the time space between consecutive pulses.
A further object of the invention is a method of converting amplitude modulated pulses into an equivalent analog signal by producing a continuously interpolated signal from a generated cosine.sup.2 function signal in accordance with the amplitude of the successive digital signals as alternately decoded in parallel memory channels.
Other objects, advantages, and features of the invention will become apparent from the following specification and appended claims when taken with the accompanying drawings.